Apparatus for generating, controlling, and utilizing air currents



May 17, 1927. v a CUR 1,629,437

APPARATUS FOR GENERATING, CONTROLLING, A ND UTILIZING A IR CURRENTSFiled D60. 28, 1923 KSheets-Sheet l May 17,1927. M629 4 5. CURTI vAPPARATUS FOR GENERATING, ooumo'bi'iffi. A'ND uTILIzIN HR cunannfi FiledDec; 28, 1923 3 Shoots-Sheec 5 1,629,437 May 17,1921. E'CUR v APPARATUSFOR GENERATING, CONTROLLING, AND UTILIZING AIR CURRENTS Filed Dec. 28.1923' 3.Shoeta-Sheet s F'glb' 7' Egg Patented May 17, 1927.

UhlllED STAEE S PATENT OFFICE. I

ERNESTO CURTI, OF MILAN, ITALY.

AP?ARATUS FOR GENERATING, CONTROLLING, AND UTILIZING AIR CURRENTS.

Application filed December 28, 1923, Serial No. 683,254, and in ItalyJanuary 8, 1923.

The invention consists in generating, that the invention secures thefollowing adtransmitting and utilizing in special machine vantages: rtools, violent pressure air currents of instan- The arrangement can workon small taneous character and slow suction air curair volumes and yetsupply an efficient hamrents separated by stationary periods; or meringaction even when the generator is 5 slow pressure air currents andinstantaneous running at a low number of revolutions; suction currents,all of which phases may hence a minimum consumption of motive follow oneanother in any desired sequence power.

required for the operation of the tools (2). Tools and generators ofminimum concerned. size can be used, with short stroke and small 6 Thesuccession of the said phases, which weight, and consequently lesscumbersome. may be determined at will, enables the These features ensurea wide field for the achievement of the following main objects: mostvaried applications.

' A violent pressure followed by a slow suc- The annexed drawingsillustrate, by way tion and by a likewise short stationary of exampleonly, method and means for period permits of obtaining an eilicientcarrying the invention into execution.

powerful blow even with an engine running Figs. 1 and 2 show the aircurrent generat a low number of revolutions per minute; ator inlongitudinal section and side view of causing the hammer to rise Withoutrespectively.

thumping against the top end of the cyl- Figs. 3, l, 5 and 6 show camsof various indcr; and of fully restoring the air presprofiles foractuating the generator piston. sure in the piping connecting the toolto Fig. 7 is a longitudinal sectional view of the generator. a toolspecially adapted for stone chiselling.

A. slow pressure followed by a sudden Fi 8 and 9 illustrate two types ofpressuction and by a long stationary period persure regulating valves. 7mile of a good working of such tools as Fig. 10 illustrates a rammingtool used require a heavy striker, such as hammers, for concrete work,road making and the pestles and the like working by gravity. like. 7

A violent pressure followed by a sudden Figs. 11, l2, 1.3, 14 illustratean apparatus :1 suction and a long stationary period permits speciallyadapted for drilling rocks etc. a good working of high speed tools. If,Fig.15 illustrates an apparatus specially however. the striker of saidtools is heavy, adapted for drilling machines.

a quick pressure followed by a slow suction Fig. 16 illustrates acompressor with two without any stationary period will prove pumpbarrels.

E more suitable. Fig. 17 illustrates a high power striking By insertinga valve at any desired point tool. in the connecting piping between thegenera- Fig. 18 illustrates a high speed apparatus tor and thetools, thevalve checking the working as a hammer. air flow only in a givendirection or in the Figs. 19, 20, 21 show another apparatus oppositeone, the piping portion comprised with revolving tool.

between the said valve and the tool will be Figs. 22, 23 show toolsdirectly coupled traversed only by a current of pressure air up to thegenerator. I or onlyby a current of rarefied air; and a Figs. 24, 25show a modified form of the continuous air flow between the generatorgenerator, in which the spring operating the ant. the special tools willbe realized withupward stroke of the piston is dispensed out need ofinstalling any intermediate air with. vessel. In this manner the lossesdue to The generator (Figs. 1 and 2) comprises: heating of the air willbe avoided and a A shallow cylindrical chamber-1 arranged, maximumefficiency secured. 1 V for instance, vertically and formed in the 50From the foregoing it will be apparent machine base onwhich also thedriving elec- .1

trio motor is erected. In the chamber 1 reciproeates a piston 2, inwhose hollow piston rod is lodged a helical compression spring 5, thespring action being adjustable by means of the screw-cap 6. The oppositeend of the spring bears against the top end ol the chamber formed in thepiston rod. The. spring 5 accordingly tends to force the piston againstthe ceiling ofthe chamber 1, the piston rod 2 projecting through thesaid'cei'l' ing-and reciprocating in a packing-gland. The bottom of thechamber 1 is provided with large openings 1", so that atmosphericpressure is exerted on the lower face of the piston 2. The pistonreceives arcciprocating movement, so that in the. upper closed portionor the chamber 1 compressions and expansions are alternately set up.Atth-e end ot'each' downward stroke atmospheric pressure is r storedthrough openings ll.' u "1 fl'i, (,1 b i 1. 1 V .e p n (no s lone 1scausec y tie spring 5, whereas the downward stroke is caused by themotor, through a cam 10 fitted on an extension of the motor shaft andactuating the top end of'the'pistonrod through a-ro'ller 7 carriedby'anarm-S' pivoted on the bracket The length of 9. 11 is :1 bleedpassageway. the piston stroke will obviously-be given by the differencebetween the minimum and the maximum cam radius, and the piston movementwill conform to the cam profile, so that during a cam. revolution:

The piston may have stationary periods in correspondence to a camportion whose profile lS concentric to-the axis of the-camshaft;

TllGPlSDOIl may movein a sudden, erking way in both directions andthrough the full stroke length in correspondenceto steps in the camprofile The piston-canperform'more than one stroke during-a singlerevolution of the'cam and these strokes may be otthe same or ofdiii'erent lengths.

So for instance the profile of the cam 10' shown in F 3 will cause thepiston 2 to make a practically instantaneous upward stroke owing to thenose a, and adownward stroke at a'unitorm' and'consequently slow speed,due to the spiral portion 6. 7

The profile' o tthe cam 10 according to Fig, 4 causes the pist'on tomakea practically instantaneous upward stroke due to the-nose a, and arelatively slowdownward stroke due to the spiral k ey 7)" followed by astationary period at the bottom end of the stroke due to the concentricportion a, the

duration of the stationary period being slightly in excess of ahalfrevolution ofthe cam shaft.

The profile ot'the cam 10" according to Fig. 5 isac apted to cause thepiston to make a downwardstroke at a gradual speed owing to the doublespiral portion 7) during one complete revolution of the cam, the saidstroke being followed by a stationary period owing to the concentricportion 0 lasting for about half a revolution of the cam.

The profile of the cam 10 according to Fig. 6 causes the piston to makea double stroke at a gradual speed for each complete revolution of thecam, owing to the symmetrical portions cl and d and the noses a.

Fig. 7 shows a tool specially suitable for stone and'niarble chiselling,plate caulking and the like. Thecylinder 16, in which plays thestriker17 actuatingthe underlyingchiscl, ism-titted at the top with ahandle 13 and a lever 14 operating a member 15 by which the inlet thepiping121is controlled. Thestriker 17, when nearingthe end of its upwardstrokeygently engages the elastic cone 18 and isthen brought to stop.lVhen an' instantaneouspressure comes, the striker disengaged from saidelastic stop --and driven -with full force downwards against theunderlying chisel. A valve provided bovetheelastic cone 18 enables airto pass from the outside into the tool in-order to fill'the' piping 12-during all the time the generator remains inoperative.

In some cases it-may'be required-that the pressure or depression, thoughpractically instantaneous, yet shall beiowered-just before they ceaseln-sueh cases an adjustable valve opening inwardly, or reversely, islittedtothepump barrels. Bywayof exanr pile two valve-types, onesingle-acting andtth'e other double-acting, are shown in'Figs. '8 and 9respectively for the said purpose. They may-be fitted either on thetools, or onthe connecting pipings or on thepump barrel or chamberoutlet. As closing member in the valve an annular'fl'exib'le doublediaphragm 565'( is-provided. When lying in its normal position,-thediapl ragm closes a circular set of holes 22'23, either totally orpartially. lV-hendeflected, it uncovers the saidholes andth'erebycauses'the piping 'to communicatefiwith the atn'iosphere as aconsequence oft-"a rise or ota fall of the imienpressure relatively=tothe outer pressure.

In the'rammingdevice' for concrete work, roadmaking and the likeaccording to Fig. 10, 26 is theflatbeater, Q l th'e cylinder, 27 thecover to 'which'a hand-1e (not shown in the figure) is fitte'd,'-25 isthe piston with the long piston rod required in this special lowered, inorder that the pressure existing above the piston may not hinder theformation of the vacuum required for its next quick upward stroke. Thelatter valve serves to facilitate the restoration of atmosphericpressure in the generator at the end of each stroke. 1

Fig. 11 represents an apparatus utilizing the impulses supplied by thegenerator across the connecting piping 120. This apparatus is speciallyintended for rock-drilling and accordingly comprises a drill whichautomatically rotates about its axis. In the cylinder 48 is arranged arotatable tube 32, fitted with an enlarged bottom end (Figs. 11 and 14).The cylinder 48 (Figs. 12 and 13) has two channels 36 and 42 dividedinto two chambers by the vanes 37 and 43 rigidly secured to the tube 32.The same air impulses that cause the striker 34 to rise and fall andtherewith to deal blows on the drill head, enter the channels 3642 andby impinging against the said vanes, cause them to swing like a pistonin a revolving cylinder. A ratchet gear comprising the pawl 46 and thecompression spring 50 (Fig. 13) transmits the swinging motion of thevanesto the ratchet wheel 47 and to the drill rigidly secured therein.The air from the. generator also enters the channels 31, and thecylinder 32 communicates with the said channels through the holes 33.Accordingly, if the striker 34 is in its highest position, it will beviolently. forced downward against the drill head. The air will thenenter the channel 36 through the hole 35, this hole being uncovered whenthe striker has reached its lowest position. This air will impingeagainst the vanes and make the cylinder or tube 32 turn until the holes33 are covered and the holes 38 uncovered,

whereby the channels 31 will be placed in communication with the'portionofthe tube 32 lying below the underside of the striker 34. The hole 39will be placed into communication with the hole 40 and thus permit theair that has remained in the tube 32 above the striker 34 to escape. tothe atmosphere. The air that has rushed into the cylinder 32 through theholes 38 will force the striker upward and bring it back to its startingposition. The striker in moving upward will uncover the hole 41 and thuscause the air to enter the channel 42 and impinge again the vane 43. Inthis manner also the tube 32 will be restored to its starting position,that is to say, with the holes 33 in communication with the channels 31,and the holes 38 covered. Furthermore the tube 32 will block off thecommunication between the ports 39 and 40, and establish it, instead,between the ports 44 and 45 in orderto permit the escapement of the airfrom under the striker 34 so as not to hinder the next downward strokeof the striker.

currents and with a distributor.

Fig. 15 digrammatically shows an apparatus in which the working tool isfitted with rotating mechanism alone. This is the typical case fordrilling machines. The apparatus is substantially identical with thewhen a high amount of striking energy is required. The apparatus workssimilar to the type illustrated by Figs. 1 and 7, but with two pipings62 and 63 leading respectively from the top and bottom halves of thesame generator chamber 60. This chamber has two air bleeds 11 and 61,and the pipes are connected to the chamber by nipples 65 and 66.

Fig. 1.8 shows a tool working a high velocity hammer, with twocontinuous air The apparatus comprises a cylinder connected to anothercylinder 70. Cylinder 70 actuates a distributor 68;vhereas in thecylinder 7O reciprocates astriker 71 to which a rod 71 is attached. Theupper portion of the cylinders 70-70 is fitted with a cover plate 75.The continuous air current from the piping 67 enters the chamber 70 ofthe distributor 68 and forces the distributor downwards, thusestablishing a communication between the inner port 72 and the outerport 73. In this manner the air entrapped in the cylinder 70 under thestriker 71 is allowed to escape to the atmosphere. Atter this acommunication will be established through the port 69 between the airsupplied by the pipe 67 and the space above the striker 71. The airimpinging against the striker 71 will cause it to deal. a sharp blow tothe work. I In this phase, the generator compresses the air and works incoujunction with the pipe 67 while the piping 68 is inoperative, so asto overcome the eventual resistances to the downward swinging of thedistributor 68. In the next phase the generator sets up a stationaryphase in the piping 67 and a pressure phase in the piping 68 and allowsthe distributor 68 to rise and revert to its former position. The hole72 will let air into the cylinder 70 below the striker 71, thus forcingthe striker upwards. The hole 69 will communicate with the external hole74 and permit the air in the space above the striker 71 to escape to theatmosphere. The valves 76 and 77.

serving to render the air flow a continuous one. may be fitted at anydesired point of the pipings 67 and 68 and are of the pattern describedabove.

till

Fig. 19 shows another tool .fitted with a revolvingdistributor andadaptedto work also at considerabledistances. The apparatus comprisesa-cylinder 81; having abottom 82 and a cap 83. Theair delivered into thecylinder by the piping 90 and is controlled by the distributor S4.lVithin .the cylinder 81 reciprocates the striker 85 formed integralwith the rod 85. When the parts concerned are in the position shown inFig. 19, special ducts provided inside of the rod 85 allow theairexisting in the cylinder space below the striker 8-3 to pass into thechamber 87 and thence, througlrSS. into the chamber-'90 of the cap, 83,where it impinges on the vane 89 forming part oi the (llStTlbU'tOl 84(Figs. 20-21). The distributor at this moment will. be in thepositionshownin Fig. 21 and the hole 91 for the top inlet will not register withthe hole 92 in the cylinder end, thus closing the air inlet andpreventing the air outlet through the hole 93. because this hole doesnot register with the hole 941 nor with the hole 104: opening-to theatmosphere. On the contrary there are open the lover inIet hole 95 andthe upper outlet hole 97. The hole 95 registerswith the hole 96 to medin the cylinder plate, and the hole 97 communicates with thecorresponding cylinder and the external hole 105. I wish to point outthat only the inlet holes 91-95 are in communication wi h the airdelivered by the piping 90. The outlet holes 93-97arc alternately set incommunication with the atmosphere through the holes 1 and 105 formed inthe outer periphery of cover 83. Accordingly, the air impinging upon thevane 89 will force it and cause the distributor to revolve so astobringtheholes from the-position shown in Fig. intothe position shownin Fig. 21. The upper inlet hole 91 now registo s the hole 92, and thelower outlet hole 95 registers the correspondinghole 94;. The lowerinlet hole 95 and the upper outlet hole 97 are closed since they do notregister with the corresponding holes 96 and 98. At this moment air'islet into the cylinder 81 and rushing against the upper face ot'thestriker 85, forces thestriker downward so as to impart a blow to thetool, while the air existing inthe cylinder space under the striker willhave alreadyescaped through holes 102-into duct 108 and thence, throughholes 94,93, 10 1. to the atmosphere. After administering the blow onthe work, the air, finding no open outlet. will rise in pressure untilit forces open the valve 99 that opens outwardly. on through the duct100 and impinge onthe other vane 101 of the distributor, thus restoringthe distributor-to its initial position. The air will now pass, throughthe hole 95, into the circular passage 103, andthence,

through the holes 102, into the cylinder This air will then pass spacebelow the striker 85. The striker will thus be forced upwards and theair above it will escape through the holes 9?, .98, 10:"). In order toprevent- 85 from striking the bottom end 82 ot' the cylinder 81. the rod85 has a reduced portion '86, past which, a little before the stril' rer'85 reaches the bottom end of its downward stroke, tlie air rises to-actuate the distributor in the manner already described above.

Figs. 22 and 23 show two embodiments in which the tool is coupled to thepump barrel directly. InFig. 22 the double-acting piston 2 actuates thestriker- 17 .ot the tool 16 by means of two pipes. Th'eetle'ct. of thepressure supplied'byfone pump barrel adds itself to the effect of thedepression supplied at the same instantby theotherpnmp barrel. Iii-Fig.23 a single-acting chamber {1 is provided, the same working only on thetop face of the striker 17, which is raised and lowered in unison dueto'theinovement ot'the piston 2. V

The generator according to the modified form represented by F igs, 2stand is operated without the assistance oflthe spring "5 and exhibitsallth e features ofthe generator already describe'chthe soled'irler'encebeingthat the spring 5 e'l'l'ecting the .pistons return toits formerposition' is eliminated.

The'ifu'nction of the spring. in this instance is performethby'a slotcam106' tormedin the fly-wheel 110. the said slot engaging a roller'107secured to the top. endoit'the rod l of the piston2.

This sloteffects the downward as well as the upward stroke of thepiston.

.In the chamber 1 reciprocates the piston 2, whose rod 4 has securedtogits top end a roller 10?. The roller is constantly. engaged by a slotca1n106 forined in a fly-wh'eel 110 V keyed to the shaft 109', thisshaft being driven by the motor 108 inany convenient manner, forinstance through gear wheels 1'11, 112. r

The .slot cam106I1nay be given a great variety of forms so as to impartto the piston 2 diiier'ent movements in accordance with the requirementsof the specialapplh cations for which the generator is used.

Having now described myinvention and how the same is to j becarried out,what I claim asmy invention is:

1. A generatorifor producing gasjcurrents in different phases comprisinga rotatable cam member. a cylinder; a piston' reciproeating in saidcylinder, a pipe communicating with the cylinder-tor placing the.cylinder in communication with a gas operated toohand means including.the cainfor mov ing the piston forcibly and rapidly in one dn'ection andfor moving "it gradually and slowlyin the opposite direction. 1

2. A generator as claimed'in claim l'in whichth'e-last mentioned meansholdsthe piston stationary at one end of the cylinder during a partialrevolution of the cam.

A generatoros claimed in claim 1 in which the last mentioned meansincludes a piston rod and {L spring for forcing the piston rod towardsthe cam.

4. An apparatus as claimed in claim 1 including a second pipe connectedto the cylinder, one pipe being connected to one end portion of thecylinder and the other pipe being connected to the other end portion ofthe cylinder, whereby the piston is doubleecting.

In testimony whereof I aflix my signature.

ERNESTO CURTI.

